Project Summary/Abstract Hook-up behaviors (HUBs; i.e., sexual activity outside an exclusive relationship with no mutual expectation of romantic commitment) are a prevalent problem on college campuses partly due to their association with alcohol use and sexual assault. HUBs and sexual assault frequently co-occur, and HUBs are positively associated with college men?s sexual assault perpetration. Prior research supports the relationship between alcohol use and HUBs, as well as sexual aggression perpetration; however, there is limited understanding into individual difference factors that increase the risk of alcohol-facilitated consensual and coercive HUBs. Alcohol Myopia Theory (AMT) suggests alcohol intoxication creates a narrowing of attention to salient environmental factors (e.g., rewarding sexual experiences). The dual systems model of risk-taking suggests that socio-emotional system factors such as positive urgency (i.e., a tendency to give into impulses when positive affect is high) and the expectation that alcohol use will result in positive sexual outcomes, such as heightened intimacy and/or arousal, (i.e., alcohol-related sexual expectancies) increases sexual risk-taking. An integrated AMT and dual systems model would suggest that the risk of alcohol-facilitated HUBs may depend on the presence of distal socio-emotional system factors that increase the likelihood of sexual risk-taking behaviors. The overall objective of the proposed study is to elucidate the temporal associations between alcohol use and engagement in consensual and coercive HUBs among college men, and to identify the moderating effects of positive urgency and alcohol- related sexual expectancies, utilizing a daily diary design. No prior research has examined the relationship between college men?s alcohol use and HUBs and whether positive urgency and alcohol-related sexual expectancies moderate the temporal association between alcohol and HUBs. Guided by the dual systems model and AMT, the proposed study will advance the understanding and prevention of sexually risky behaviors. The specific aims of this proposed study are to: (1) evaluate whether trait positive urgency moderates the temporal association between alcohol use and HUB and (2) evaluate whether alcohol-related sex expectancies moderate the temporal association between alcohol and HUBs. The proposed study will examine these factors in 250 college men as they relate to the under-explored sexual activity of HUBs, utilizing an innovative daily diary design. The proposed study is significant because it will inform researchers and prevention and intervention programs by identifying specific risk factors to address in the prevention of alcohol-facilitated consensual and coercive HUBs.